this is surely documentet but...i've discovered just now
Blessed potion of carrot juice can inprove your Pe just to 25
the "smell of carrots" room can inprove Pe limitless (5 notch for potions obviously)
very usefull in ID dive, (i've find a "lot" of special rooms and increased PE to 74 only by carrot potion)
and now i play with excange potions:p